This disclosure relates to an energy efficient method and apparatus for production of an alkyl aryl ether and a diaryl carbonate.
Diaryl carbonates, such as diphenyl carbonate are an important reactant in the production of polycarbonate resins. As the use of polycarbonate resins has increased, the efficient production of diaryl carbonate has become of greater importance because polycarbonates can be manufactured by reacting bisphenols (e.g., Bisphenol A) with diaryl carbonates. Diaryl carbonate production involves two reaction steps. First, a dialkyl carbonate reacts with an aromatic alcohol to produce an alkyl aryl carbonate and an alkyl alcohol in presence of a transesterification catalyst. Next, two molecules of the alkyl aryl carbonate undergo a disproportionation reaction to produce one molecule of diaryl carbonate and one molecule of dialkyl carbonate. Alkyl aryl ether, such as anisole, is a side product in this process and is produced by the reaction of dialkyl carbonate and aromatic alcohol. Alkyl aryl ether is also produced by decarboxylation reaction of alkyl aryl carbonate.
The side product alkyl aryl ether from diaryl carbonate production is purged from the process along with aromatic alcohol and dialkyl carbonate. This purged stream comprising alkyl aryl ether may not be suitable for use in any other synthesis as it may contain dialkyl carbonate and aromatic alcohol. So while there is a process to purge alkyl aryl ether from diaryl carbonate manufacturing process, currently there is no process for co-production of alkyl aryl ether along with diaryl carbonate in an energy efficient process.